With rapid advancement of the fabrication technology of a thin film transistor liquid crystal display (TFT-LCD), the LCD is largely applied in various electronic products such as a Personal Digital Assistant (PDA) device, a laptop, a digital camera, a video camera, and a mobile phone due to the fact it has advantages of smaller size, less weight, lower power consumption and low radiation. Moreover, the quality of the LCD is ceaselessly improved and the price thereof is continuously decreased since manufacturers aggressively invest in research & development and employ large-scale fabricating equipment. That promptly broadens the applied fields of the LCD.
Please refer to FIG. 1, the structure of a typical LCD panel is illustrated. Generally speaking, in the fabricating procedures of LCD panels, processes such as film depositing and lithography are applied repeatedly to fabricate considerable quantities of thin film transistors (TFT), pixel electrodes, scan lines and data lines arranged in a crisscross pattern for constructing the pixel array on a lower glass substrate 10. Then, an upper glass substrate 12 with a color filter manufactured thereon is disposed over the lower glass substrate 10. And a liquid crystal layer is inserted and sealed between the upper and lower glass substrate 12 & 10 to constitute the LCD panel.
For providing the desired voltage and signals to operate the thin film transistors of each pixel device, on the peripheral areas of the panel some circuits, chips and devices are fabricated. As shown in FIG. 1, beneath the lower glass substrate 10 a printed circuit board 14 is connected. The printed circuit board 14 has a timing controller chip and several source driver IC chips 16 thereon for electrical connecting to each pixel device via the data lines on the LCD panel. Each source driver IC chip 16 is respectively connected to display panel with a flexible bus 18 and electrical connected to the pixel devices via the circuit patterns formed on the display panel.
Except the source driver IC chips 16 below the display panel, some gate driver IC chips 20 are fabricated on the right area of the lower glass substrate 10 for connecting to each pixel device via the scan lines. It is noted that, generally, these gate driver IC chips 20 are fabricated directly on the lower glass substrate 10 by the chip on glass (COG) technique. Because the reserved area on the right side of the display panel is very narrow, the gate driver IC chips 20 are disposed and connected in cascade along the right edge of the display panel. By using some WOA (wire on array) lines defined on the lower glass substrate, all the gate driver IC chips are connected together in a series.
However, when the size of display panel desired is unceasingly increased, both the number of the gate driver IC chips 20 and the length of the WOA lines 22 are raised so as to cause the resistance and the loading too high. Especially, the width of each WOA line 22 on the lower glass substrate 10 is merely 50 micron, so the high resistance of the WOA lines 22 will severely degrade the signal intensity. And because each gate driver IC chip 20 also possesses considerable resistance, the decreasing signal intensity cannot effectively operate related devices when the number of the gate driver IC chips in cascade is increasing. Especially for the gate driver IC chips 20 arranged in the rear end of the series, the excessive degraded signals and voltage cannot drive the pixel devices effectively so as to result in serious loading problems.